Extraction machines, which are moved back and forth along a conveying device for the extracted coal, are used in underground extraction devices, e.g. for the extraction of coal. In the case of extraction devices of this type, which can be up to 400 m in length, special troughs are arranged in each case in the face end region in order to create the necessary installation space, not only to be able to drive the extraction machine as far as into the face end region, but also to be able to arrange the drives for the conveying device, and where applicable the extraction machine, in the face end region. Corresponding special troughs can consist, in particular, of so-called connecting troughs (shearer loader operation), in which the distance between upper run and lower run is increased in order, subsequently, to guide the chain about a chain wheel, and/or of wedge troughs (ploughing operation) where, in addition, the distance between the machine guide and the side member becomes increasingly greater over the length of the trough pan. Machine guide parts which are detachable from the trough pan in order to be able to undertake repairs on the plough, on the shearer loader or on the conveyor chain in the face end region are used in particular in the case of said special troughs. Securement between the detachable attachment and the trough pan is effected by means of connecting devices with a fitting and a counter fitting which are able to be locked using at least one retaining piece. The main scope of the present invention concerns corresponding wedge troughs and connecting troughs with detachable attachments for plough or shearer loader extraction plants. In principle, however, the invention is also applicable to other attachments which have to be detached from the trough pan.
A generic connecting device is known from DE 20 2004 001 476 U1 and the known connecting device includes, among other things, hook elements in the lower region of the side members, into which the detachable machine guide part is inserted by means of holding pieces, such that a separable hook joint connection is created in the lower region. In the case of the generic connecting device, the attachment and the side member only have to be prevented from pivoting apart by way of the retaining piece, to which end the retaining piece is realized either as a retaining strip that can be screw-connected in place or it is in the form of crescent-shaped liners which project beyond the side part and, in their turn, are secured against detachment by means of a screw bolt. The placing in position of the machine guide can certainly be made easier by using the hook joint connection. However, the detaching in particular of the screw bolt is cumbersome and time-consuming and can be made considerably more difficult, in particular, by the jamming of the bolts, liners or the retaining strip.
DE 202007000263 U1 makes known connecting means for shearer loader operations, said connecting means including retaining vices that jut out from the trough pan and wedge jaws that can be placed thereon in order to secure the attachments, which are provided with penetration windows for the retaining vices, on the trough pan.